Early full-color light emitting diode (“LED”) luminaires included red, green, and blue LEDs. These LEDs were of poor quality, had low output powers, and suffered from highly-variable performance characteristics. Since the introduction of the first full-color LED luminaires, advancements in LED technology have produced luminaires that include additional light sources and are capable of providing higher output powers.
Luminaires that include multiple light sources have conventionally been controlled using three basic techniques. The first technique uses simple controls to allow a user to adjust each color source individually. The user is able to modify the intensity value of each light source from, for example, zero to full-scale using separate controls, such as linear faders, dials, or a numeric keypad. Controlling the output of a luminaire in such a manner requires a user to have knowledge of color theory and the manner in which light combines in order to obtain a desired color output. Such a control technique has practical limitations which limit its use to relatively simple color systems (e.g., three light source systems). The second technique involves controlling the hue, saturation, and intensity (“HSI”) of a luminaire using three separate controls or a graphical color map of a color space. The HSI technique allows the user to pick a color within the color space between three points (i.e., a color within the triangle defined by the positions of the red, green, and blue light sources within the color space, or the positions of the secondary colors cyan, magenta, and yellow within the color space). The third technique involves a list of commonly named or numbered colors which correspond to lighting filters (i.e., gels) that are used in theatre and television lighting. The user selects a name or number of a desired color, which is subsequently looked up in a table of component color values.
Each of the above techniques is based on a three color system, and the three colors available in such systems are used to generate each color output. Such systems are commonly used in TV cathode ray tubes (“CRTs”), flat panel displays, and variable color luminaires.